Pension and Postretirement Plans (Obligation, Asset, and Funding Information) (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	$ 1,286,694,000	$ 1,160,897,000
Service cost	18,221,000	18,687,000	$ 20,461,000
Interest cost	46,787,000	47,925,000	51,608,000
Amendments	7,183,000	75,000
Actuarial (gain) loss	(81,851,000)	73,191,000
Acquisitions	0	58,600,000
Benefits paid	(63,852,000)	(74,506,000)
Special termination benefits	0	1,825,000
Curtailment	(836,000)	0
Settlement	(95,777,000)	0
Benefit obligation at end of year	1,116,569,000	1,286,694,000	1,160,897,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	2,343,471,000	2,042,490,000
Actual return on plan assets	(63,715,000)	375,487,000
Employer contributions	0	0
Benefits paid	(63,852,000)	(74,506,000)
Settlement	(95,777,000)	0
Fair value of assets at end of year	2,120,127,000	2,343,471,000	2,042,490,000
Funded status	1,003,558,000	1,056,777,000
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	110,082,000	106,526,000
Service cost	819,000	858,000	985,000
Interest cost	3,865,000	4,233,000	4,384,000
Amendments	1,028,000	0
Actuarial (gain) loss	(7,552,000)	4,041,000
Benefits paid	(5,694,000)	(5,576,000)
Benefit obligation at end of year	102,548,000	110,082,000	106,526,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	0	0
Employer contributions	5,694,000	5,576,000
Benefits paid	(5,694,000)	(5,576,000)
Fair value of assets at end of year	0	0	0
Funded status	(102,548,000)	(110,082,000)
Other Postretirement Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	22,785,000	24,171,000
Service cost	892,000	1,028,000	1,386,000
Interest cost	620,000	779,000	1,230,000
Amendments	(12,473,000)	0
Actuarial (gain) loss	(2,519,000)	(2,830,000)
Acquisitions	0	516,000
Benefits paid, net of Medicare subsidy	(782,000)	(879,000)
Benefit obligation at end of year	8,523,000	22,785,000	24,171,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	0	0
Employer contributions	782,000	879,000
Benefits paid, net of Medicare subsidy	(782,000)	(879,000)
Fair value of assets at end of year	0	0	$ 0
Funded status	$ (8,523,000)	$ (22,785,000)